The present invention is applicable to different types of prostheses, preferably leg prostheses, but for illustrative, but not limiting purposes, it will be described in the following how the invention can be utilised in order to create a damping device for damping in a vertical direction. When damping, it is often desirable to maintain the relative orientation between the components to which the damping device is connected during the damping phase. For leg prostheses, this can imply that it is desired to maintain the angle between the lower leg and the foot blade during vertical damping.
Leg prostheses according to prior art can be provided with a shock-absorbing action for absorbing a vertical load during foot strike. Damping in a vertical direction is particularly desirable in extreme situations, for example when a user steps down from a kerb, gets off a bus, descends a staircase, or the like. For this purpose, the lower leg member usually exhibits a so-called axial damping device, being arranged in the lower leg itself. The damping device can include two overlapping tubes, which can be displaced in relation to each other in an axial direction when loading the prosthesis, and a spring, which is arranged to counteract this movement. One disadvantage with these prostheses, however, is their relatively large mounting length.
Leg prostheses of this type are often useless for persons who, for example, are amputated relatively far below the knee joint, since these leg prostheses due to the integrated damping device have a mounting length which is too large. If the leg prosthesis has a mounting length, i.e. a distance from the underside of the foot blade to the point of attachment to the leg, being larger than the corresponding amputated portion, the prosthesis is out of the question for that person.